ESA has opened an Announcement of Opportunity for scientific studies in areas of advanced Global Navigation Satellite System (GNSS) research under the European GNSS Evolution Programme. With this call, the Agency intends to foster the scientific utilisation of EGNOS and Galileo and to gather feedback from the scientists for the designers and integrators of the next generation of navigation satellites, with a view to maximising the scientific value of the exploitation of European GNSS signals and data.